Effect of He-Ne laser radiation on healing of osteochondral defect in rabbit: a histological study

This study examined the influence of low-level laser therapy (LLLT) on the healing of a large osteochondral defect in rabbits.An osteochondral defect with 5 mm diameter was surgically induced in the right femoral patellar groove of 48 adult male rabbits. They were divided into a control and an experimental group. The rabbits were treated at 2, 4, 8, and 16 weeks after surgery, with six rabbits in each study period being tested at each biweekly period. The experimental group received LLLT with a helium-neon (He-Ne) laser (632.8 nm, 10 mW) of 148.4 J/cm(2) three times a week, and the control group received placebo LLLT with equipment switched off. The defects were examined macroscopically and microscopically. The results of the histological examination 2 weeks after surgery showed that the osteochondral healing of the control group was significantly accelerated compared with that of the experimental group. However, the osteochondral healing of the experimental group 4 weeks and 16 weeks after surgery showed that healing accelerated significantly compared with that of the control group. The conclusion was that LLLT with an He-Ne laser could not significantly accelerate healing of a large osteochondral defect in rabbits of the experimental group compared with that of the control group throughout the duration of the present study.